While there are proposed various methods and apparatuses for carrying out character recognition by using a multi-valued digital image, a recognition target of such a character recognition apparatus is generally a binary image. Then, in the case of a multi-valued image, it is necessary to once binarize the multi-valued image before inputting the datum. Recognition performance of the character recognition apparatus is dependent on accurate segmentation of a character as a recognition target, out of a background that is not the recognition target. In the meantime, as a method in order to determine a binarizing threshold value for binarizing a multi-valued image, for example, there is proposed and disclosed a character recognition apparatus using a discrimination analysis method (for example, refer to Patent Document 1).